Static Coupling Impact Check (static_coupling)

Spectre Syntax

title static_coupling node=[n1 n2 ...] vnth=<value> vpth=<value> <inst=[inst1inst2...]> <xinst=[xinst1 xinst2...]> <subckt=[subckt1 subckt2....]> <xsubckt=[xsubckt1 xsubckt2....]> pwl_time=<value> <depth=n> error_limit=<value>

SPICE Syntax

.cck title static_coupling node=[n1 n2 ...] vnth=<value> vpth=<value> <inst=[inst1inst2...]> <xinst=[xinst1 xinst2...]> <subckt=[subckt1 subckt2....]> <xsubckt=[xsubckt1 xsubckt2....]> pwl_time=<value> <depth=n> error_limit=<value>

Description

Evaluates the possible coupling effects in the circuit.

For each victim node, the check identifies its coupling impact from aggressor(s) by dividing the total charge of the aggressor with its node capacitance (including cc+gc+device cap). The charge of each aggressor is calculated by multiplying the voltage level of the coupling aggressors (using Vmax for worst case analysis) with the coupling capacitance. In this check, only the capacitors written in netlist are counted.

The results are written to a file with the extension static.xml, which can be viewed with a Web browser.

Arguments

node	Nodes to which the check is applied. Default is none.
error_limit	Maximum number of errors reported. Default is 100.
vpth	PMOS threshold voltage. This value is used to calculate the voltage drop across a PMOS channel during voltage propagation. Default is -0.4 V.
vnth	NMOS threshold voltage. This value is used to calculate the voltage drop across an NMOS channel during voltage propagation. Default is 0.5 V.
pwl_time	Time for pwl source to be considered as constant vsource.
inst	Subcircuit instances to which the check is applied. Default includes all instances (inst=*).
xinst	Subcircuit instances to be excluded from the check. Default is none.
subckt	The instances of the specified subcircuit to which the check is applied. Default includes all subcircuits (subckt=*).
xsubckt	The instances of the specified subcircuits that are excluded from the check. Default is none.
depth	Hierarchy levels (starting from top, instance, or subcircuit scope) to be checked. Default is 8.

Example

Spectre Syntax

coup static_coupling node=[*] 

SPICE Syntax

.cck coup static_coupling node=[*] 

The above statement reports all victims that are impacted by aggressors. The following is an example of the report that is displayed in the Web browser:

This report has the following two sections:

• The first section displays the node name of the victim. Next, the node capacitance (with respect to ground) of the victim is shown. The min/max voltage columns display the possible voltage range for this node. The coupling impact is a gauge used to measure the coupling impact of aggressor(s) on the victim. The coupling impact is a relative term and does not have any physical meaning.
• The second section displays the list of aggressors. The min/max voltage columns display the possible voltage range for this node. The coupling instance name (and its capacitance) is the capacitor connected between the aggressor and the victim. This section can have multiple rows for multiple aggressors.

Related Topics

Static Checks

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